How acute lymphoblastic leukaemia (ALL) is diagnosed
Usually you will see your GP, who will examine you and arrange a blood test. If the results of the test suggest you may have leukaemia, your GP or a haematologist from the local hospital will contact you.
A haematologist is a doctor who specialises in the treatment of blood problems. They will arrange for you to be seen quickly at the hospital for further tests and treatment.
Most people with ALL are referred for treatment at a specialist haematology unit in the hospital. The haematologist will ask you about your general health and any previous medical problems. They will examine you and do a blood test to check the numbers of all the different types of blood cell.
If the blood test shows leukaemia cells in your blood, the haematologist will want to take a sample of your bone marrow. This is the most important test for diagnosing ALL. It shows the exact type of leukaemia you have and provides information that the doctors need to plan the best treatment for you.
A doctor or nurse takes a small sample of bone marrow from the back of the hip bone (pelvis) or occasionally the breast bone (sternum). It’s sent to a laboratory to be checked for abnormal white blood cells. A haematologist can tell which type of leukaemia it is by identifying the type of abnormal white cell.
The procedure can be done on the ward or in the outpatients department. It takes about 20–30 minutes in total but removing the bone marrow sample only takes a few minutes.
Before the bone marrow sample is taken, you’ll be given a local anaesthetic injection to numb the area. You may also be offered a short-acting sedative to reduce any pain or discomfort during the test.
The doctor or nurse passes a needle through the skin into the bone. They then draw a small sample of liquid from inside the bone marrow into a syringe. This is called a bone marrow aspirate. It can feel uncomfortable for a few seconds when the liquid marrow is drawn into the syringe.
You may also have small core of marrow taken (a trephine biopsy). The doctor or nurse passes a thicker needle through the skin into the bone marrow. When they take the needle out, it contains a small core of bone marrow.
You may feel bruised after having a sample of bone marrow taken, and have an ache for a few days. This can be eased with mild painkillers.
This test can be done on a blood or bone marrow sample. It shows which type of lymphocyte (B-lymphocyte or T-lymphocyte) has become cancerous. Knowing this helps the doctors plan the most appropriate treatment for you.
This test can also be used to look for very small amounts of leukaemia during treatment and at the end of treatment.
Cytogenetics and molecular tests
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Cytogenetics is the study of chromosomes. Every cell in our body has 22 pairs of chromosomes and two sex chromosomes: XX in women and XY in men. Chromosomes are made up of DNA, which is grouped into genes. The genes control all the activities of the cell.There are often changes in the DNA in leukaemia cells. There are several ways of looking for these changes.
This looks at the chromosomes through a microscope. Usually the chromosomes from 20–30 cells are looked at. It is possible to see if there are extra chromosomes or fewer than there should be. Sometimes bits of chromosomes are lost completely and other times they have moved to a different chromosome. Some people with ALL have a particular change in the leukaemia cells, called the Philadelphia chromosome (see below).
FISH (fluorescence in situ hybridisation)
This test is used to look at specific areas in the genes where changes are known to be found in ALL. It can find changes that can’t be seen with cytogenetic testing.
PCR (polymerase chain reaction)
This is a very sensitive test that can usually detect one abnormal cell in 10,000 normal cells. It looks for specific changes in the DNA of your blood cells. In ALL, it is often possible to find a change that is specific to your leukaemia cells. Your doctors can use this to see how many leukaemia cells(minimal residual disease)there are in the bone marrow at the beginning of treatment, during it and at the end.
Doctors use the PCR test to see how successful a treatment has been. They also use it to plan whether you need further treatment and what type of treatment.
Some people with ALL have a change in the leukaemia cells called the Philadelphia chromosome. This is called Philadelphia positive ALL (Ph+ ALL).
The Philadelphia chromosome develops when part of chromosome 9 wrongly attaches to part of chromosome 22. This creates a new gene, called BCR-ABL (see diagram below), which causes the cell to make too much of a protein called tyrosine kinase. This then causes the bone marrow to produce abnormal blood cells.
The Philadelphia chromosome is only in the leukaemia cells. It isn’t inherited and can’t be passed on to your children. Your doctors can give you more information.
This test is done to check for leukaemia cells in the central nervous system (CNS). The CNS is made up of your brain and spinal cord. Your doctor will talk to you about whether you might need a lumbar puncture.
A small sample of the fluid that surrounds your brain and spinal cord is taken to check for leukaemia cells. Your doctor uses a local anaesthetic to numb the lower part of your back and then passes a needle gently into the spine. They then take a small sample of the fluid to be checked for leukaemia cells.
Having a lumbar puncture may be uncomfortable, but it only takes a few minutes. You will then be asked to lie flat for at least half an hour. Your doctor or nurse will advise you how long.
Some people may have a headache after a lumbar puncture. If this happens let your doctor know so that they can prescribe painkillers for you. Drinking plenty of fluids (three litres a day) for the next two days can help to reduce headaches. We have more information about having a lumbar puncture.
You will have this blood test if a donor stem cell transplant may be a part of your treatment.
Your tissue type is based on a group of proteins on the surface of your cells, called human leukocyte antigen markers (HLA markers). The immune system uses these markers to identify each cell in the body as one of its own.
Once the doctors know what your tissue type is they can use this to find a possible stem cell donor for you.
Your doctor may arrange for you to have other tests. These will be to check your lymph nodes for signs of leukaemia, and to assess your general health. Tests may include body scans, x-rays, further blood tests, and heart scans. Your doctor or specialist nurse can give you more information about any tests you have.
It will probably take several days for the results of your tests to be ready. This waiting period can be an anxious time. It may help to talk things over with a relative or close friend. You can also contact our cancer support specialists.
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